Opening ways
for new medicines
Our laboratory provides in vitro ADMET tests of product candidates to facilitate drug development projects with most attractive efficiency and timeline
News
March 01, 2018
Key Preclinicals participates in 17th Annual World Preclinical Congress
(June 18-21, 2018, The Westin Copley Place | Boston, MA).
The 17th Annual World Preclinical Congress focuses on the latest trends and technologies impacting drug discovery and translational research. The Congress offers a unique opportunity for chemists, biologists, pharmacologists, cancer researchers, neuroscience scientists, toxicologists, bioengineers, screening experts and translational scientists in industry and academia as well as technology providers to come together and exchange expertise and opinions. World Preclinical Congress is a key networking event yielding new partnerships that accelerate preclinical research and translation across all therapeutic areas.
About
The Key Preclinicals laboratory for primary drug trials provides an advanced highly-efficient and solid framework of services to companies and academic institutions performing pharmaceutical and biotech research. Available among our products is a variety of in vitro ADMET tests, for the full list please follow this link.
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Services
The list of currently available services include the following in vitro ADMET tests:
LogP, LogD: hybrid HPLC/shake-flask method
Volume of distribution (log Vss): bio-mimetic chromatography method
Unbound volume of distribution (log Vdu): bio-mimetic chromatography method
Coagulation assay (thrombin, Xa factor, plasmin): photometric method (IC50, Ki)
Solubility: HT Thermodynamic Method
Solubility is one of the most essential physicochemical properties of drug candidates and its measurement is an important component in the in vitro profiling of drug-like properties. The early assessment of this property during the discovery stage provides valuable information for better interpretation of the screening results and designing of new molecules. Compounds with low aqueous solubility can often produce erroneous results during functional assays, thus increasing the risk of obtaining false hits or leads. In addition, compounds with low aqueous solubility tend to be highly bound to plasma proteins with poor tissue distribution and increased potential of CYP enzyme inhibition. Measuring solubility in early stage drug discovery process can identify potentially ambiguous activity data such as false negatives due to poor solubility therefore improving the overall efficiency of activity screening and hit identification.
Highlights:
HT Thermodynamic method – enables rapid and accurate evaluation of a large number of compounds
Solubility is determined by dispensing a solid compound into a solvent (DMSO and PBS) with further HPLC quantification
Results from thermodynamic solubility determinations more frequently refer to a crystalline phase
Resulting concentrations are dependent on compound purity, ionization states, stability in solution and other factors such as solution temperature and pH
LogP: Shake Flask Method
The LogP - octanol-water partition coefficient (or simplified LogP) of a compound is a key parameter used in drug design and regulatory compliance, in the new-chemical manufacturing industry (environmental impact compliance), and in the environmental field (environmental fate of toxic substances). It has been widely used for: design of drugs and pharmaceuticals, prediction and correlation of bioconcentration and soil and sediment sorption of organic pollutants, research on medicinal chemicals, modeling of environmental fate of organic chemicals, toxicology of substances.
Despite the possibility to calculate this parameter, the precision of obtained data might be different from experimental causing in increasing discrepancy in biological tests. Therefore experimental determination of LogP/LogD is essential basic step prior "hits" evaluation.
Shake Flask LogP/LogD method is based on OECD Guidelines for the testing of chemicals supplemented with HPLC method for octanol-water system.
Highlights:
The classical and most reliable method of logP determination
The partition coefficient is defined as the ratio of the equilibrium concentrations of a dissolved substance in a two-phase system consisting of two largely immiscible solvents
Concentrations of compound in each phase are quantified with HPLC method
Low amount of solid compound is required (further diluted in DMSO) to perform the test
Solubility: HT Kinetic Method
Solubility is a crucial physicochemical property for drug candidates and is important in both drug discovery and development. Solubility of a substance may be defined as maximum amount of that substance which can be dissolved in a particular solvent at given temperature, pressure and condition. Poor solubility is detrimental to absorption after oral administration and can mask compound activity in bioassays in various ways. Hence, solubility liabilities should ideally be identified as early as possible in the drug development process. With the increasing number of compounds as potential drug candidates, solubility assays for high throughput screening enabling rapid evaluation of a large number of compounds are becoming increasingly important.
Highlights:
Uses only a few samples and allows rapid determination of solubility
The non-equilibrium solubility method can be used during early drug discovery of new chemical entity and for lead optimization
The purpose of the measurements is to identify compounds that do not have good kinetic solubility even in aqueous buffer containing DMSO, to guide modification of structures to improve solubility, and to guide formulation selection for animal dosing
Kinetic solubility data vary with the conditions of the solution: small changes in pH, organic solvent, ionic strength, ions in solution, co-solutes, incubation time, and temperature can result in large changes in the solubility of a compound
(Data sheet is under development)
Volume of Distribution: bio-mimetic chromatography method
The pharmacologically active compound is intended to interact with the target enzyme or receptor. However, only very small fractions of the administered drug actually achieve the goal in vivo. The distribution of the compound in the body depends on its affinity for many other components, such as proteins, nucleotides and phospholipids. Since they are present in much larger volumes than the target enzyme or receptor, they significantly reduce the concentration of the active substance at the site of action. The distribution of the drug molecule in vivo depends on its properties. It may have higher local concentrations in certain tissues or organs.
Based on Klara Valko methods of bio-mimetic chromatography, Key Preclinicals developed the modified model for evaluation of volume of distribution using exclusively HPLC.
Highlights:
Bio-mimetic chromatography allows to model in vivo distribution and estimate affinity of a compound for human non-specific binding components by using human proteins and phospholipid as biorelevant stationary phases
The basic principle of the methodology is that the retention time of a compound (as a part of the mobile phases) passing through the HPLC column (containing three biorelevant stationary phases) is directly proportional to its affinity/dynamic equilibrium with the stationary phase
Application of bio-mimetic chromatography reduces animal testing and late stage attrition, lowers candidate selection cost and allows early dose estimation
We have modified the original methodology (by K. Valko) to implement it for high-accuracy volume of distribution detection. It has been successfully validated using experimental literature data for known compounds.
Brain Tissue Binding: bio-mimetic chromatography method
Estimating the unbound fraction of drugs in brain has become essential for the evaluation and interpretation of the pharmacokinetics and pharmacodynamics of new central nervous system drug candidates. A number of brain binding assays have been developed and some of them are widely applied in central nervous system (CNS) research. Many of the methods are similar to plasma protein binding (PPB) methods with slight modifications. Equilibrium dialysis with brain homogenate to measure brain tissue binding is the gold standard method and is widely applied in drug discovery research and development. Key Preclinicals offers in-house developed modification of Klara Valko method of bio-mimetic chromatography to assess brain tissue binding using exclusively HPLC.
Highlights:
Bio-mimetic chromatography allows to model in vivo distribution and estimate affinity of a compound for human non-specific binding components by using human proteins and phospholipid as biorelevant stationary phases
The basic principle of the methodology is that the retention time of a compound (as a part of the mobile phases) passing through the HPLC column (containing three biorelevant stationary phases) is directly proportional to its affinity/dynamic equilibrium with the stationary phase
Application of bio-mimetic chromatography reduces animal testing and late stage attrition, lowers candidate selection cost and allows early dose estimation
We have modified the original methodology (by K. Valko) to implement it for high-accuracy brain tissue binding detection. It has been successfully validated using experimental literature data for known compounds.
Lung Tissue Binding: bio-mimetic chromatography method
The lungs are pharmacologically active organs affecting the blood concentrations of drugs given intravenously. The lungs can take up, retain, metabolize and delay the release of many drugs and compounds.
Pulmonary surfactant is a mixture of lipids and proteins (approximately 90% lipids and 10% proteins), which is secreted by type II epithelial cells into the alveolar space. Its main function is to reduce surface tension at the air/liquid interface in the lungs. This is achieved by forming a surface film consisting of a monolayer that is enriched with dipalmitoylphosphatidylcholine (in all mammalian species, the surfactant contains approximately 80% phosphatidylcholine) and two-layer lipid-protein structures that are closely related to it.
Studying and assessing the pharmacokinetic function of the lungs is very important in drug development process. Based on Klara Valko methods of bio-mimetic chromatography, Key Preclinicals developed the modified model for evaluation of lung tissue binding using exclusively HPLC
Highlights:
Bio-mimetic chromatography allows to model in vivo distribution and estimate affinity of a compound for human non-specific binding components by using human proteins and phospholipid as biorelevant stationary phases
The basic principle of the methodology is that the retention time of a compound (as a part of the mobile phases) passing through the HPLC column (containing three biorelevant stationary phases) is directly proportional to its affinity/dynamic equilibrium with the stationary phase
Application of bio-mimetic chromatography reduces animal testing and late stage attrition, lowers candidate selection cost and allows early dose estimation
We have modified the original methodology (by K. Valko) to implement it for high-accuracy lung tissue binding detection. It has been successfully validated using experimental literature data for known compounds.
(Data sheet is under development)
Plasma Protein Binding: bio-mimetic chromatography method
The effect of organic compound binding to blood plasma proteins (Plasma Protein Binding (PPB)) is of particular interest in ADME studies, since the bound compounds, according to the “free drug hypothesis” hypothesis, cannot interact with their protein target. However, these interactions are also important for the creation of sustained release dosage forms [1, 2]. The role of plasma protein binding is recognized as a major factor in the distribution and effectiveness of a potential drug.
Although immunoglobulins, lipoproteins, fibrinogen and phospholipids contribute significantly to binding, and they can also greatly contribute to lower free drug concentrations, it is generally accepted that binding mainly occurs to a greater extent with human serum albumin (HSA) (it binds mainly hydrophobic and negatively charged compounds) and alpha-1-acid glycoprotein (AGP or AAG) (it binds positively charged compounds).
Based on these proteins, Klara Valko developed methods of bio-mimetic chromatography to evaluate PPB using exclusively HPLC. We offer PBB assessment using the modified methodology based on her previous work.
Highlights:
Bio-mimetic chromatography allows to model in vivo distribution and estimate affinity of a compound for human non-specific binding components by using human proteins and phospholipid as biorelevant stationary phases
The basic principle of the methodology is that the retention time of a compound (as a part of the mobile phases) passing through the HPLC column (containing three biorelevant stationary phases) is directly proportional to its affinity/dynamic equilibrium with the stationary phase
Application of bio-mimetic chromatography reduces animal testing and late stage attrition, lowers candidate selection cost and allows early dose estimation
We have modified the original methodology (by K. Valko) to implement it for high-accuracy plasma protein binding (PPB) detection. It has been successfully validated using experimental literature data for %PPB of known compounds.
Unbound volume of distribution (log Vdu): bio-mimetic chromatography method
Good in vitro efficacy and selectivity does not necessarily mean good in vivo efficacy due to poor absorption, high metabolic rate, or simply low free concentration in vivo. Binding to plasma proteins and tissue binding lower the free concentration of the drug molecule in vivo. At that, in order to maintain the necessary effectiveness, it is required to raise the dose of the drug, which may increase the risk of side effects.
Since plasma proteins are present in high concentrations, even weak interactions can cause a slight decrease in the free concentration of the drug. The unbound volume of distribution (Vdu), which is defined as the dose / concentration of free plasma, gives a better estimate of the free drug available for interaction with the target in vivo than the binding of plasma protein per se.
Based on Klara Valko methods of bio-mimetic chromatography, Key Preclinicals developed the modified model for evaluation of unbound volume of distribution using exclusively HPLC.
Highlights:
Bio-mimetic chromatography allows to model in vivo distribution and estimate affinity of a compound for human non-specific binding components by using human proteins and phospholipid as biorelevant stationary phases
The basic principle of the methodology is that the retention time of a compound (as a part of the mobile phases) passing through the HPLC column (containing three biorelevant stationary phases) is directly proportional to its affinity/dynamic equilibrium with the stationary phase
Application of bio-mimetic chromatography reduces animal testing and late stage attrition, lowers candidate selection cost and allows early dose estimation
We have modified the original methodology (by K. Valko) to implement it for high-accuracy unbound volume of distribution detection. It has been successfully validated using experimental literature data for known compounds.